Chandler, Ariz. To help designers save development time and cost, Microchip Technology Inc. has designed a pair of 16-bit I/O expanders to provide system I/O expansion through existing microcontroller serial ports.

The MCP23017 and MCP23S17 are designed with hardware-address pins that allow multiple devices to be cascaded in one system. That allows designers to add up to 128-bits of I/O to existing systems without having to redesign it with a higher I/O MCU.

The MCP23017 and MCP23S17 can support a broad range of applications with low and high-bandwidth requirements. The MCP23017 is the only 16-bit I/O expander that supports standard (100-kHz), fast (400-kHz) and high-speed (up to 1.7-MHz) I²C communications, according to the company.

The MCP23S17 features SPI (serial peripheral interface) clock speeds up to 10-MHz for higher throughput applications.

Both I/O expanders operate down to 1.8-V and have a standby mode in which current consumption is less than 2-µA. Separate interrupt outputs for each bank of 8 I/O ports can be used for system partitioning. Pins can drive standard LEDs directly (25-milliamps sink/source capability per I/O).

The MCP23017 and MCP23S17 complement the 8-bit MCP23008 and MCP23S08 I/O expanders. See story link below.

Samples and volume production are available today. Packaging is lead-free and includes 28-pin PDIP, SOIC, SSOP and 6X6 millimeter QFN options. In 1,000-unit quantities and 28-pin PDIP packaging, the MCP23017 and MCP23S17 are priced at 86 cents and 91 cents, respectively.